The present invention relates to an occupant protecting device for protecting an occupant on the seat of a vehicle, such as an automobile, in a collision, and particularly, to an occupant protecting device that prevents the body of the occupant from moving forward in a head-on collision.
Occupant protecting devices include systems for protecting the occupant of an automobile in a collision in which the front of a seat cushion is raised in a car collision in order to prevent a submarine phenomenon in which the occupant that wears a seat belt slips through a lap belt in a head-on collision.
Japanese Unexamined Patent Application Publication No. 7-81466 (incorporated by reference herein) discloses an occupant protecting device which has a bag placed under the front of a seat cushion and a plate placed on the bag and in which the plate is pushed up by the bag when the bag is inflated, as shown in FIGS. 3(a) and 3(b) of the present application. FIGS. 3(a) and 3(b) show the configuration of the occupant protecting device in JP7-81466. A floor 5 of a seat cushion 4 has a recess 6 formed slightly offset forward from the waist H of an occupant, and an air bag module 7 is installed inside the recess 6. The upper side of the recess 6 is covered with a plate 9 that can open in front on a rear hinge 8.
The air bag module 7 installed in the recess 6 has therein an air bag 7a in a folded state. The air bag module 7 is connected to a sensor provided in a strategic point of the car body. When the air bag module 7 receives a signal from the sensor, it operates a gas generator to deploy and inflate the air bag 7a upward.
As shown in FIG. 3(b), when the air bag 7a deploys and inflates upward, the plate 9 is lifted. Since the plate 9 is fixed at its rear end by the hinge 8, it is brought into a fixed front-open inclined state by being lifted by the air bag 7a. Therefore, the plate 9 in the inclined state enters the lower portion of the seat cushion 4, and increases the density of the seat cushion 4 to harden the seat cushion 4, thereby restraining the waist H of the occupant from moving forward.
In the above described occupant protecting device disclosed in Japanese Unexamined Patent Application Publication No. 7-81466, the plate 9 is substantially flat. As a result, the plate 9 receives an extremely large reactive force from the seat cushion 4 when the air bag 7a inflates and pushes up the plate 9. Therefore, in order to provide for proper operation of the device it is necessary to provide a high-power gas generator which achieves high gas pressure sufficient to overcome the reactive force from the cushion 4.